In other words, against this specific
disease, applying the label rate of a
DFZ product is like putting on many
times the label rate of Rally. Each fungal
colony is different, but on average,
it takes about 40 units of Rally
to provide the same level of fungal
inhibition as one unit of DFZ, which
is why these latter products work better
when both are used at comparable
rates.

b. Vivando is a new product that
received its first EPA registration in
2011. It is a fungicide that controls
powdery mildew only, but has shown
outstanding activity against this disease
in our trials.
For example, it provided 100%
control on Chardonnay clusters subjected
to extreme disease pressure:
high carryover inoculum from the
year before, no sprays whatsoever
before bloom, untreated vines and
those with various ineffective treatments
scattered elsewhere throughout
the block, 14-day spray intervals
(Table I). Vivando represents a new
class of chemistry, so there are no
cross-resistance issues and it should
be a very useful “big gun” addition
to rotational programs with other
materials.

c. Luna Experience is a new product
that received EPA registration in
February 2012. Like many new fungicide
products, it is a combination of
two active ingredients. The one that
counts is fluopyram, a new “Group 7”
material in the same class as boscalid
(the non-strobie component of
Pristine). It has shown excellent activity
against both powdery mildew and
Botrytis in several trials that we have
run, which is consistent with results
I have seen from a number of other
locations. (The second component of
Luna Experience is tebuconazole, the
DMI active ingredient in the former
product, Elite. Unfortunately, formulation
of this new product is such that the lowest

labeled rate provides just a
fraction of the tebuconazole that Elite
once did, and it is unlikely to be of
much benefit, especially in vineyards
with any significant history of DMI
use). CAUTION: At press time,
fluopyram had not been approved
for any wines exported to Japan.

Like virtually all new fungicides,
the Group 7 materials are at risk of
resistance development and must be
rotated with other classes of chemistry
in order to keep from burning
them out. Remember, Luna
Experience and Pristine both contain
one of these materials, so should not
be considered rotational products for
one another.

2. Sulfur – We do not use dusting
sulfur (too much rain), but sprayable
formulations are very popular. A few
years ago, we conducted numerous
experiments with sprayable sulfurs to
get a better handle on various aspects
of their activity. A few highlights:

• Sulfur provides very good protective
activity on sprayed tissues, but
not on new leaves that emerge after
the last application. No kidding.

• However, sulfur provides excellent
post-infection control when applied
up through the time that young colonies
start to become obvious (about
six or seven days at 80°F). Although
it does have some eradicant activity
against raging infections (see below),
it is significantly stronger against the
younger colonies. Practically speaking,
this means that when a PM spore
lands on a new, unprotected leaf produced
since the last application (see
above), there is still time to hit it with
the next spray in a post-infection
mode if that is applied thoroughly
and before mildew is easy to see.
Australian researchers have reported
similar results.

• As noted above, post-infection
sprays applied to heavily-diseased
tissues are much less effective than

those applied to incubating or very
young colonies. Sulfur is not the
material of choice as an eradicant if
you reach the “Omigod!” stage. That
would be Stylet Oil or the similar
PureSpray Green (or perhaps Oxidate,
at a much higher cost).

Remember that once the leaf or
berry cells beneath a well-established
mildew colony have been sucked dry
by the fungus, nothing will bring
them back to life even if the mildew is
eradicated. The best that an eradicant
spray can do is to keep things from
getting much worse, it cannot raise
the dead. Never forget that the results
you obtain will only be as good as the
spray coverage you can provide.

• We were unable to demonstrate
any negative effects of low temperatures
on either the protective or
post-infection activities of sulfur. In
a number of repeated tests, control
was the same at 59°F as it was at 82°F
when we sprayed with the equivalent
of 5 lb/A of Microthiol. Workers from
Australia also reported no differences
in control at 59°, 68°, or 86°F when
used at this rate, although there was
a slight decrease in activity at 59°F
when the rate was reduced down to
1.7 lb/A.

• Rainfall of 1 to 2 inches decreases
sulfur’s protective activity significantly.
Not surprisingly, this effect
is more pronounced with generic
“wettable” formulations than with
so-called “micronized” formulations
(e.g., Microthiol), which have smaller
particle sizes so adhere better to tissue
surfaces. These latter formulations
cost more for a reason. The
negative effects of rainfall can be
somewhat compensated for by adding
a “spreader-sticker” adjuvant to the
spray solution and/or increasing the
application rate.